1. Technical Field
The present invention relates to computer aided design, and more particularly to systems and methods for fast and accurate integrated circuit design tools.
2. Description of the Related Art
Fast and accurate circuit simulations and analysis are required to capture rapidly-changing device features, intrinsic device fluctuation, and random mismatch among adjacent devices in integrated circuits. Numerical device simulations (i.e., technology computer aided design (TCAD) based on drift-diffusion or hydrodynamic transport with partial differential equations are physically accurate tools. However, simulation run-time is significantly extended due to complex computations and computational overhead. Furthermore, to achieve and understand “statistical” distributions is very challenging in TCAD-aided analysis and for design for manufacturability (DfM) applications.
For circuit functionality at the macroscopic level, conventional statistical methods are typically based on threshold voltage (Vt), channel length (L), and channel width (W) distributions. These parameters include the use of standard deviations for Vt, L, and W. Thus, the application of conventional statistical methods is limited to critical circuits such as SRAM and eDRAM circuits (e.g., in mixed-mode simulations). However, a domain not adequately addressed thus far is the device or process functionality at the microscopic level. Statistical analyses should address device or process functionality and yield using different-level parameters beyond the macroscopic level of conventional circuit analysis tools.